External fixator strut

ABSTRACT

The present disclosure provides an external fixation strut for an external fixation device having a ball joints that can be attached to the outer or inner surface of the ring and locked to increase overall stability of the external fixation device. Some embodiments of the fixation strut include a first ball joint coupled to a first end portion of a strut housing, the strut housing having an axial bore defined therethrough. A second ball joint is coupled to a second end portion of an elongated member. The elongated member is coupled to an adjustment mechanism, which is coupled to an upper end portion of an adjustment sleeve. The adjustment sleeve is slidably disposed in the axial bore of the strut housing, and is used to effect coarse strut length adjustments. Gradual strut adjustments are effected by translating the elongated member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation application of U.S.application Ser. No. 12/864,807, filed on Jul. 27, 2010, which is anational phase filing under section 371 of PCT/US2009/033603, filed Feb.9, 2009, which claims the priority of U.S. Provisional Application61/027,408, filed Feb. 8, 2008, each of which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

The present disclosure relates in general to the field of externalfixation, and more specifically, to external fixator connection strutsand other connection rods.

BACKGROUND

Without limiting the scope of the disclosure, this background isdescribed in connection with external fixation devices and specificallyconnection struts and rods. Generally, external fixation devices arecommonly used in a variety of surgical procedures including limblengthening and deformity correction. The process involves a rigidframework comprising several rings that are placed externally around thelimb and attached to bone segments using wires and half pins insertedinto the bone segments and connected to the related section of theexternal rigid framework. The opposite rings of the rigid framework areinterconnected by either threaded or telescopic rods directly or inconjunction with uni-planar or multi-planar hinges, which allows thesurgeon to adjust position of the rings relative to each otherlongitudinally, rotationally, horizontally or angularly over a period oftime.

For example, in limb lengthening, the bone is surgically divided intotwo segments and wires and half pins are inserted into bone segmentsabove and below the surgical bone cut and attached to rings of a rigidframework interconnected by struts or telescopic connection rods. Therigid framework is used to gradually push the two bone segments apartlongitudinally over a period of time (e.g., one millimeter a day). Thisallows the bone to gradually form in the gap between bone segmentscreated by this distraction technique. Once the desired amount oflengthening is achieved (e.g., 5-6 cm), the external apparatus isstabilized into a fixed position and left on the bone segments untilcomplete mineralization of the newly formed bone (e.g., 3-6 months,depending on the nature of pathology and amount of lengthening).

Similarly, in deformity correction, the bone is surgically divided(usually at the apex of the deformity) into two segments and wires andhalf pins are inserted into bone segments above and below the surgicalbone cut and attached to rings of a rigid framework. Opposite rings ofthe rigid framework are connected together by threaded rods withattached uni-planar or multi-planar hinges and angular distractor thatis used to gradually push the two bone segments apart angularly over aperiod of time.

One common fixation device is a circular metal structure known as theIlizarov Apparatus. The Ilizarov apparatus, when used for limblengthening or deformity correction, consists of several rings or archesthat are placed externally around the limb and attached to surgicallyseparated bone segments using wires and half pins. For limb lengthening,the opposite rings are interconnected directly by three or four threadedor telescopic rods that are regularly adjusted in length and allowed forgradual separation of bone segments longitudinally. For angulardeformity correction, the opposite rings of the Ilizarov apparatus areconnected by a pair of hinges that provide an axis of rotation for bonesegments and an angular distractor that gradually pushes two rings andassociated bone segments apart.

Another common external fixation device is the Taylor Spatial Frame,which is a hexapod type external fixation device based on a Stewartplatform but shares many components and features of the Ilizarovapparatus. The Taylor Spatial Frame consists of two external fixationrings attached to bone segments by wires and half pins and connectedtogether by 6 telescopic struts with multi-planar hinges located at bothends of the strut. Each strut may be lengthened or shortened asnecessary to either pull two interconnected ring segments towards eachother or push them apart. Adjustment of strut length allows manipulatingwith bone segments acutely or gradually in 6 axes (e.g.,lengthening/shortening external/internal rotation, anterior/posteriorhorizontal translation, medial/lateral horizontal translation,anterior/posterior angular translation, and medial/lateral angulartranslation) to perform limb lengthening and correct angular,translational and rotational deformities simultaneously.

The Taylor Spatial Frame includes a plurality of struts interconnectinga pair of rings. The wires, half pins, struts and other connection andassembly elements of the frame are connected to the rings via aperturesdefined therein. All of those apertures or holes are located on the samering surfaces extending through the upper ring surface to the lower ringsurface. This creates a positioning problem for wire and half pinattachment and placement of the additional connection rods and assemblyelements due to the competition for holes in the fixation ring of theframe or the wires and pins interfering with the connections of thestruts to the holes.

Each strut of the Taylor Spatial Frame has a threaded rod partiallydisposed inside of a hollow shaft, and the hollow shaft includes anadjustment nut that mates with the threaded rod. To effect either acoarse adjustment (rapid strut length adjustment) or a fine adjustment(gradual strut length adjustment) to the length of the strut, the samethreaded rod is pulled out or pushed in relative to the hollow shaft.Because the threaded rod has a finite length, however, using the samethreaded rod for rapid strut length adjustment limits the total amountof threaded rod available for gradual strut length adjustment during,for example, limb lengthening and deformity correction. As a result, atime consuming exchange of the struts for longer ones during thetreatment is required.

Additionally, the replacement or removal of a strut from the TaylorSpatial Frame during the course of treatment is impossible without usingexternal support or other stabilization mechanism to support the rest offrame. The struts of the Taylor Spatial Frame are required to beconnected at the top or bottom of the rings. Such connections requirethe use of either ball joints in the holes of the rings or universaljoints extending from the top or bottom surfaces of the rings. TheTaylor Spatial Frame, however, does not include any locking mechanismfor temporarily locking the universal joints or ball joints in theirorientation. As a result, if one strut is removed from the frame, itwould become unstable and collapse.

The universal joints and ball joints of the Taylor Spatial Frame alsomake strut length adjustments inaccurate and inconvenient. The joints ofthe Taylor Spatial Frame allow each strut to have three degrees ofrotational freedom, including an undesirable degree of freedom for axialrotation. As such, when the adjustment nut of a strut is rotated axiallyto effect a strut length adjustment as discussed above, the entire strutwould also rotate axially, thereby keeping the threaded rod of the strutfrom translating relative to the hollow shaft of the strut. To allow thethreaded rod to translate as desired, one would have to use a secondhand or a vice to secure the hollow shaft from axial rotation. Absentsuch an inconvenient step, strut length adjustments would be inaccurate.

Both types of joints have additional drawbacks. One drawback for usingball joints is that there is insufficient spatial clearance for the balljoints to effect some adjustments to the orientation of the struts andthe rings. A drawback for using universal joints is the decrease in thefunctional length of the struts due to the space taken up by the lengthof the universal joints. Another drawback is the instability caused byuniversal joints. The universal joints each include at least one hingeconnection, in which a pivot pin is commonly and loosely held by tworotating parts that are designed to rotate about the longitudinal axisdefined by the pivoting pin. Due to the loose coupling between therotating parts and the pivoting pin, a degree of undesirabletranslational movement is inherent in the design of the hinge connectionand introduces instability to the Taylor Spatial Frame.

SUMMARY

Various embodiments of an improved external fixation strut is includedin this disclosure. In one embodiment, the external fixation strutincludes a strut housing having an axial bore defined therethrough, afirst ball joint coupled to an end portion of the strut housing, and anadjustment sleeve slidably disposed within the axial bore, theadjustment sleeve and the strut housing being releasably coupled by aconnector. The external fixation strut further includes an externallythreaded elongated member, a second ball joint coupled to an end portionof the threaded elongated member, and an adjustment mechanism comprisinga rotation element. The rotation element has an internally threaded boredefined therethrough, wherein the threaded elongated member is disposedthrough the threaded bore, the external thread of the elongated memberand the internal thread of the threaded bore mating with each other suchthat rotating the rotation element would cause the threaded elongatedmember to translate. The adjustment mechanism is rotatably coupled to anend portion of the adjustment sleeve, and the adjustment mechanism isoperable to rotate but not translate relative to adjustment sleeve.

Also included in the present disclosure are various embodiments for amethod of interconnecting first and second fixator rings with a strut,adjusting the strut to a pretreatment strut length, and making desiredstrut length adjustments during treatment. The rings each comprising aplurality of apertures defined in the inner or outer side surface of thering. In one embodiment, the disclosed method comprises providing afirst part of a strut comprising a first ball joint coupled to an endportion of a strut housing, the strut housing having an axial boredefined therethrough, the first ball joint comprising a first ball stud.The method further includes providing a second part of the strut. Thesecond part includes a second ball joint coupled to an end portion of athreaded elongated member, the threaded elongated member beingthreadably coupled to an adjustment mechanism, wherein the adjustmentmechanism is rotatably coupled to an end portion of an adjustmentsleeve, the adjustment mechanism being operable to rotate but nottranslate relative to the adjustment sleeve. The second ball jointscomprises a second ball stud. The method further includes slidablydisposing the adjustment sleeve within the axial bore of the struthousing. The method further includes connecting the ball stud of thefirst ball joint to a first aperture of the first ring, and connectingthe ball stud of the second ball joint to a second aperture of thesecond ring. Other steps included in the disclosed embodiment of themethod include positioning the adjustment sleeve relative to the struthousing to arrive at the pretreatment strut length, and releasablycoupling the adjustment sleeve to the strut housing.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the features and advantages of thepresent disclosure, reference is now made to the detailed description ofthe disclosure along with the accompanying figures and in which:

FIG. 1 is a perspective view of one embodiment of an external fixationstrut of the present disclosure.

FIG. 2 is an exploded view of the external fixation strut of FIG. 1.

FIG. 3A is a cutaway view of one embodiment of an external fixationstrut of the present disclosure.

FIG. 3B is a cutaway view of another embodiment of an external fixationstrut of the present disclosure.

FIG. 3C is a focused, cutaway view of the external fixation strut ofFIG. 3B.

FIG. 4A is a perspective view of a embodiment of the external fixationstrut of the present disclosure.

FIG. 4B is a perspective view of a portion of the external fixationstrut shown in FIG. 4A.

FIGS. 5A, 5B, 5C and 5D are perspective views of portions of embodimentsof an external fixation strut of the present disclosure.

FIG. 6A is a perspective and cutaway view of a ball joint lockable by asplit ball joint cage.

FIG. 6B is a perspective and cutaway view of the ball joint of FIG. 6A.

FIG. 6C is a perspective and cutaway view of another ball joint lockableby a split ball joint cage.

FIG. 7 is a perspective view of a ball joint lockable by a threaded balljoint cage cup.

FIG. 8 is a perspective view of a ball joint lockable by split ball.

FIG. 9 is an exploded view of a ball joint lockable by a set screw.

FIG. 10 is a side view of one embodiment of the external fixation strutof the present disclosure attached to the outer surface of an externalfixation device.

FIG. 11 is a side view of one embodiment of six external fixation strutsof the present disclosure attached to the outer surface of an externalfixation device.

FIG. 12A is a perspective view of an embodiment of an external fixationstrut of the present disclosure.

FIG. 12B is a cutaway view of an embodiment of an external fixationstrut of the present disclosure.

DETAILED DESCRIPTION

While the making and using of various embodiments of the presentdisclosure are discussed in detail below, it should be appreciated thatthe present disclosure provides many applicable inventive concepts thatcan be embodied in a wide variety of specific contexts. The specificembodiments discussed herein are merely illustrative of specific ways tomake and use the disclosure and do not delimit the scope of thedisclosure.

To facilitate the understanding of this disclosure, a number of termsare defined below. Terms defined herein have meanings as commonlyunderstood by a person of ordinary skill in the areas relevant to thepresent disclosure. Terms such as “a”, “an” and “the” are not intendedto refer to only a singular entity, but include the general class ofwhich a specific example may be used for illustration. The terminologyherein is used to describe specific embodiments of the disclosure, buttheir usage does not delimit the disclosure, except as outlined in theclaims.

The present disclosure provides an external fixation strut having balljoints that can be attached to the outer or inner surface of a fixationring and housing that allows for independent rapid and gradualadjustment in length. The external fixation strut includes a first balljoint having a first ball stud extending from a first ball member thatis at least partially surrounded by a first ball cage. The first ballstud attaches to an aperture in an outer or inner surface of theexternal fixator ring or other external support. The external fixationstrut includes a strut housing comprising an axial bore extendinglongitudinally from the ball cage and an adjustment sleeve slidablyfitted within the axial bore of the strut housing and a sleeve fastenerpositioned to secure the adjustment sleeve to the strut housing. Theadjustment sleeve adjusts coarse rapid longitudinal movement withrespect to the strut housing and an adjustment mechanism positioned atone end of the adjustment sleeve and threadably connected to a threadedelongated member. The adjustment mechanism gradually adjustslongitudinally the threaded elongated member and a second ball jointconnected to the threaded elongated member. The second ball jointincludes a second ball stud extending from a second ball member that isat least partially surrounded by a second ball cage. The second ballstud attaches to an aperture in an outer or inner surface of theexternal fixator ring or other external support.

FIG. 1 is a perspective view of one embodiment of the external fixationstrut of the present disclosure for an external fixation device. Theexternal fixation strut 10 includes a first ball joint cage 12 that atleast partially encloses a first ball member 14 that includes a firstball stud 16 that is operable to be received in an aperture of anexternal fixator ring or other external support (not shown) to securethe first ball member 14 of the first ball joint cage 12 to an externalfixator ring or other external support (not shown).

A telescoping strut housing 18 extends from the first ball joint cage 12and has an aperture (not shown) extending longitudinally from the firstball joint cage 12. The first ball joint cage 12 allows angular androtational alignment of the telescoping strut housing 18 relative to thefirst ball member 14. The telescoping strut housing 18 includes atelescoping housing adjustment aperture 20. An adjustment sleeve 22 isslidably disposed in the axial bore (not shown) of the telescoping struthousing 18. The adjustment sleeve 22 is slidable within the axial bore(not shown) to allow adjustment of the coarse end-to-end length of theexternal fixation strut 10 in a rapid manner. The adjustment sleeve 22includes a sleeve fastener 24 positioned through the telescoping housingadjustment aperture 20 to secure the adjustment sleeve 22 to thetelescoping strut housing 18. In some embodiments, the adjustmentaperture 20 may include preset holes for rapid longitudinal movement ofthe adjustment sleeve on the preset amount (e.g., 5 mm) relative to thestrut housing. In these embodiments, the sleeve fastener 24 can beconfigured to have a neck portion that correspond to the shape of thepreset holes for positive mechanical interference. As such, the coarsestrut length adjustment does not involve translating the elongatedmember 28 relative to the adjustment sleeve 22, and the entire length ofthe elongated member 28 is preserved for gradual strut length adjustmentas discussed below

An adjustment mechanism 26 is rotatably coupled to an end portion of theadjustment sleeve 22 and threadably connected to the threaded elongatedmember 28. As such, the adjustment mechanism 26 is operable to rotatebut not translate relative to the adjustment sleeve 22. The adjustmentmechanism 26 generally includes a rotation element having a threadedbore defined therethrough, and the threaded elongated member 28 isdisposed through the threaded bore. The threads of the threaded bore andthe threaded elongated member 28 mate with each other, allowing therotation of the rotation element to result in the longitudinaltranslation of the elongated member 28.

In the embodiments shown in FIG. 1, the adjustment mechanism 26 includesa thumbwheel seated in a groove portion (not shown) defined in an upperend portion the adjustment sleeve 22. The thumbwheel of the adjustmentmechanism 26 is gradually rotated to translate the threaded elongatedmember 28 and to adjust the overall end-to-end length of the externalfixation strut 10 in a gradual manner. The adjustment sleeve 22 includesa slot 23, through which one can observe the longitudinal position of anend portion 29 of the threaded elongated member 28 relative to theadjustment sleeve 22. As such, one can determine the amount longitudinaladjustment that was made. Although not shown in FIG. 1, it is to beappreciated that in some embodiments, the adjustment mechanism 26 mayincorporate any security mechanism known in the art to limit therotation of the thumbwheel in one or both directions so that the doctoror patient would not accidentally adjust the strut length. In oneexemplary embodiment shown in FIGS. 12A and 12B, the adjustmentmechanism 26 may include a ratchet-based locking mechanism 200 that canbe engaged or disengaged by the push of a button or lever.

The threaded elongated member 28 includes a second ball joint 30 thatincludes a second ball joint cage 32 adapted to at least partiallyenclose a second ball member 34 having a second ball stud 36, which isoperable to be received in an aperture in an external fixator ring orother external support (not shown). The skilled artisan will readilyunderstand that the first and second ball members as well as the firstand second ball studs may have one or more additional slots 40 or nuts(not shown) operably connected thereto to tighten and lock the ball orball stud in the desired positions. The slots 40 may use any type headfastener known to the skilled artisan, e.g., slotted, Phillips, hex,socket, high-torque or other fastener/head.

FIG. 2 is an exploded view of one embodiment of the external fixationstrut of the present disclosure for an external fixation device. Theexternal fixation strut 10 includes a first ball joint cage 12 that atleast partially encloses a first ball member 14. The first ball member14 passes through a ball aperture 38 that is sized and proportioned tofit the first ball member 14. A first ball stud 16 is operable to securethe first ball member 14 to an external fixator ring or other externalsupports (not shown). The first ball joint cage 12 allows angular androtational alignment of the external fixation strut 10 relative to thefirst ball member 14.

A telescoping strut housing 18 extends from the first ball joint cage 12and has an axial bore extending longitudinally from the first ball jointcage 12 to the axial bore aperture 42. The telescoping strut housing 18includes a telescoping housing adjustment aperture 20 defined in a wallof the strut housing 18. An adjustment sleeve 22 passes through theaxial bore aperture 42 and is positioned in the axial bore of thetelescoping strut housing 18. The adjustment sleeve 22 is slidablewithin the axial bore (not shown) to allow adjustment of the coarseend-to-end length of the connecting rod 10 in a rapid manner. Theadjustment sleeve 22 includes a sleeve fastener 24 that is insertedthrough an aperture 44 centrally defined in a sleeve fastener washer 46and through the telescoping housing adjustment aperture 20 into a sleevefastener aperture 48 in the adjustment sleeve 22. In the embodimentshown in FIG. 2, the sleeve fastener aperture is a threaded radial boredefined in an end portion of the adjustment sleeve. The sleeve fastenerwasher 46 can have a variety of configurations to provide various designadvantages. In some embodiments, the sleeve fastener washer 46 has asmooth inner surface (not shown). In some other embodiments, the innersurface of the sleeve fastener washer 46 has a teethed portion (notshown) cooperating with a matching teethed portion (not shown) of thetelescoping strut housing 18 to provide a more secured connection withthe strut housing 18.

An adjustment mechanism 26 is rotatably coupled to an end portion of theadjustment sleeve 22 and threadably connected to a threaded elongatedmember 28. The adjustment mechanism 26 adjusts longitudinally thethreaded elongated member 28 to adjust the overall end-to-end length ofthe connecting rod 10 in a gradual manner. The adjustment sleeve 22includes a slot 23, through which one can observe the longitudinalposition of an end portion 29 of the threaded elongated member 28relative to the adjustment sleeve 22. As such, one can determine theamount longitudinal adjustment that was made.

The threaded elongated member 28 includes a second ball joint 30. Thesecond ball joint 30 includes a second ball joint cage 32 adapted to fita second ball member 34. The second ball member 34 is fitted to a ballaperture 50 of the second ball cage 32 that is sized and proportioned tofit the second ball member 34. A second ball stud 36 is operable to bereceived in an aperture (not shown) in an external fixator ring or otherexternal supports (not shown). The second ball joint cage 32 allowsangular and rotational alignment of the external fixation strut 10relative to the second ball member 34. The skilled artisan will readilyunderstand that the first and second ball studs as well as the first andsecond ball members may have one or more additional slots 40 or nuts(not shown) operably connected thereto to tighten and lock the stud orball in the desired positions. The slots 40 may use any type headfastener known to the skilled artisan, e.g., slotted, Phillips, hex,socket, high-torque or other fastener/head.

FIG. 3A is a cutaway view of one embodiment of the external fixationstrut of the present disclosure for an external fixation device. Theexternal fixation strut 10 includes a first ball joint cage 12 thathouses a first ball member 14. The first ball member 14 passes through afirst ball aperture 38 that is sized and proportioned to fit the firstball member 14. A first ball stud 16 is operable to be received in anaperture (not shown) in an external fixation ring or other externalsupports (not shown) to secure the first ball member 14 to an externalfixator ring or other external supports (not shown). The first balljoint cage 12 allows angular and rotational alignment of the externalfixation strut 10 relative to the first ball member 14.

A telescoping strut housing 18 extends from the first ball joint cage 12and has an aperture 58 extending longitudinally from the first balljoint cage 12 to the axial bore aperture 42. The telescoping struthousing 18 includes a telescoping housing adjustment aperture 20 definedin a wall of the. An adjustment sleeve 22 passes through the axial boreaperture 42 and is positioned in the axial bore 58 of the telescopingstrut housing 18. The adjustment sleeve 22 is slidable within the axialbore 58 to allow adjustment of the coarse end-to-end length of theconnecting rod 10 in a rapid manner. The adjustment sleeve 22 includes asleeve fastener 24 that is disposed through an aperture 44 of the sleevefastener washer 46 and through the telescoping housing adjustmentaperture (not shown) into a threaded radial bore defined in an endportion of the adjustment sleeve 22. In some embodiments, the sleevefastener 24 and the sleeve fastener washer 46 are integrally connected.

An adjustment mechanism 26 is rotatably coupled to an end portion of theadjustment sleeve 22 and threadably connected to a threaded elongatedmember 28 through the adjustment mechanism aperture 60. The adjustmentmechanism 26 adjusts longitudinally the threaded elongated member 28 toadjust the overall end-to-end length of the connecting rod 10 in agradual manner. The adjustment sleeve 22 includes a slot 23, throughwhich one can observe the longitudinal position of an end portion 29 ofthe threaded elongated member 28 relative to the adjustment sleeve 22.As such, one can determine the amount longitudinal adjustment that wasmade.

The threaded elongated member 28 includes a second ball joint 30. Thesecond ball joint 30 includes a second ball joint cage 32 adapted to fita second ball member 34. The second ball member 34 passes through asecond ball joint aperture 50 that is sized and proportioned to fit thesecond ball member 34. A second ball stud 36 secures the second ballmember 34 to an external fixator ring or other external supports (notshown). The second ball joint cage 32 allows angular and rotationalalignment of the external fixation strut 10 relative to the second ballmember 34.

FIG. 3B is a cutaway view of another embodiment of the external fixationstrut of the present disclosure for an external fixation device. Thisembodiment is similar to the embodiment shown in FIG. 3A, except thatthe adjustment mechanism 26 is replaced by a gear-based adjustmentmechanism 100. As shown in FIG. 3C, which is a focused, perspective viewof the embodiment shown in FIG. 3B, the gear-based adjustment mechanism100 includes a worm gear 102 disposed in a orthogonal orientationrelative to the threaded elongated member 28, and a connecting gear 104coupling the worm gear 102 and the threaded elongated member 28. Theconnecting gear 104 has a central opening defined therethrough and teeth106. The central opening of the connecting gear allows a portion of thethreaded elongated member 28 to pass through while the teeth 106 of thesame engages the thread of the worm gear 104, thereby coupling the wormgear 102 and the threaded elongated member 28. As such, longitudinaladjustment of the threaded elongated member 28 is effected by therotation of the worm gear 104.

It is to be appreciated that adjustment mechanisms suitable for theembodiments in the present disclosure are not limited tothumbwheel-based and gear-based adjustment mechanisms that have beendiscussed. Any adjustment mechanisms known in the art can beincorporated into the embodiments disclosed herein. For example,electrical connections can be incorporated into any of the embodimentsdiscussed herein for strut adjustment by a motorized wrench as disclosedin U.S. Provisional Application No. 61/029,483, which is incorporatedherein by reference.

In embodiments in which an electrical wrench is used to make the strutadjustment. The adjustment tool may include a rotational shaft encoderor other feedback sensor that counts the number of turns of the rotatingshaft of the tool. The adjustment tool may further include a magneticfeedback sensor communicating with magnetic ring transmitter located onthe adjustment mechanism of the external fixator strut that counts thenumber of turns of the adjustment mechanism of the external fixatorstrut.

Some exemplary embodiments may include a digital ruler or feedbacksensor to determine the overall length and/or length adjustment amountof the external fixator strut. For determining the resistance during theadjustment of the external fixator strut, some exemplary embodiments mayinclude a feedback torque measurement sensor to monitor resistanceduring the adjustments of the external fixator strut and provide aturning profile.

In addition to or instead of the displays, an electrical sensor may beprovided which generates a signal when the specified target adjustmentis obtained. A display can be mechanically activated in a conventionalmanner, e.g., by an axially movable pin, a pivotably movably mountedbar, etc. Additionally or alternatively, an electrical sensor can beused in a conventional manner to generate a signal when the specifiedtarget adjustment is obtained. Signals from the electronic sensor areevaluated in a known manner by an electronic circuit in order to triggerconventional acoustic or optical devices when the target torque isobtained.

FIG. 4A is a perspective view of one embodiment of the external fixationstrut of the present disclosure. The external fixation strut 10 includesa first ball joint cage 12 that houses a first ball member 14. The firstball member 14 includes a first ball stud 16 that extends through thefirst ball joint cage 12 and is operable to secure the first ball member14 to an external fixator ring or other external supports (not shown).The first ball joint cage 12 allows angular (rotational) movements ofthe external fixation strut in three orthogonal planes in directions X1,Y1 and Z1 relative to first ball member 14. These movements allow thefirst ball joint cage 12 to be secured at different angles relative toan external fixator ring or other external supports (not shown).

A telescoping strut housing 18 extends longitudinally from the firstball joint cage 12 and has an aperture (not shown) extendinglongitudinally from the first ball joint cage 12. The telescoping struthousing 18 includes a telescoping housing adjustment aperture 20. Anadjustment sleeve 22 is positioned in the axial bore (not shown) of thetelescoping strut housing 18. The movement of the adjustment sleeve 22in the axial bore (not shown) of the telescoping strut housing 18 allowsfor an adjustment to the distance “B,” which in turn leads to a coarseadjustment to the end-to-end length “A” of the external fixation strut10 in a rapid manner.

The adjustment sleeve 22 includes a sleeve fastener 24 disposed througha sleeve fastener washer 46 and the telescoping housing adjustmentaperture 20 to secure the adjustment sleeve 22 to the telescoping struthousing 18. The telescoping housing adjustment aperture 20 also servesas a window to allow positioning and referencing of the adjustmentsleeve 22 and/or the threaded elongated member 28 to aid in theadjustment of the end-to-end length “A” of the external fixation strut10.

An adjustment mechanism 26 is rotatably coupled to an end portion of theadjustment sleeve 22 and threadably connected to a threaded elongatedmember 28. The adjustment mechanism 26 may be rotated to engage thethreads of the threaded elongated member 28, which would adjustlongitudinally the distance “C” and adjust the end-to-end length “A” ofthe external fixation strut 10 in a gradual manner. The adjustmentsleeve 22 includes a slot 23, through which one can observe thelongitudinal position of an end portion 29 of the threaded elongatedmember 28 relative to the adjustment sleeve 22. As such, one candetermine the amount longitudinal adjustment that was made.

The threaded elongated member 28 includes a second ball joint 30 thatincludes a second ball joint cage 32 adapted to fit a second ball member34. The second ball member 34 includes a second ball stud 36 that passesthrough the second ball joint cage 32 and is operable to secure thesecond ball joint 30 to an external fixator ring or other externalsupports (not shown).

The second ball joint cage 32 may be rotated in three orthogonal planesin directions X2, Y2 and Z2 relative to second ball member 34. Thismovement allows the second ball joint cage 32 to be secured at differentangles relative to an external fixator ring or other external supports(not shown). It is to be appreciated that the first ball joint cage 12of the external fixation strut may be but does not have to be orientedat the same angle, position or face relative to the second ball jointcage 32.

Graduation marks 74 are defined in or formed on the adjustment sleeve 22and telescoping strut housing 18. The graduation marks 74 are disposedproximate to the slot 23 and telescoping housing adjustment aperture 20and may be calibrated into discrete increments (e.g., one millimeterincrements) to indicate the distance between the first ball joint cage12 and the second ball joint 30, which correspond to the end-to-endlength “A” of the external fixation strut 10.

The graduation marks 74 indicate the lengths of the external fixationstrut 10 as a relative value, rather than the distance from somepredetermined specific length. The graduation marks do not necessarilyhave to be based on a traditional measuring system, or indicate theeffective length of the strut at all. For instance, the graduation markscould indicate the percentage of total rod extension, or dailyincrements for cases where the translation takes place over an extendedperiod of time. Reference to a neutral position can be useful to set thebase members at a predetermined “neutral” position.

It is to be appreciated that in some embodiments, it may be desirable tolimit the axial rotations X₁ and X₂ of the external fixation strutrelative to the first and second balls 14 and 34. For example, asdiscussed above, strut length adjustments are effected by the rotationof adjustment mechanism 26 relative to a threaded elongated member 28that is not operable to rotate axially. If the threaded elongated member28 is operable to freely rotate about its longitudinal axis, the desiredstrut length adjustment cannot be precisely effected. To ensure precisestrut length adjustment, it is desirable to limit the axial rotations X₁and X₂ of the external fixation strut relative to the first and secondball members 14 and 34. FIG. 4B is a perspective view of a portion of anexternal fixation strut that has only 2 degrees of rotational freedom(Y₂ and Z₂) relative to the first and second balls 14 and 34. The secondball joint cage 32 in FIG. 4B has a pair of bores (not shown) definedtherethrough at opposing peripheral portions, and the pair of bores areoperable to receive a pair of pins 110. The pair of pins 110 extendspartially into a radial groove 112 defined in the second ball member 34.As such, the pair of pins 110 allows the external fixation strut torotate about a first axis defined by the pins 110 and a second axis thatis orthogonal the plane define by the groove 112. The pair of pins 110,however, prevent the external fixation strut to rotate about a thirdaxis that is orthogonal to the first and second axes. Although not shownin FIG. 4B, the first ball joint cage and the first ball member 14 aresimilarly configured to include a pair of pins 110 to limit the axialrotation of the external fixation strut relative to the first ballmember 14. It is to be appreciated that in some embodiments, one pin110, rather than a pair of pins 110 is sufficient to eliminate theundesirable third degree of rotational freedom.

FIG. 5A is a perspective view of a portion of one embodiment of anexternal fixation strut of the present disclosure. The second ball joint30 includes a second ball joint cage 32 adapted to fit a second ballmember 34. The second ball member 34 passes through a second ball jointaperture 50 that is sized and proportioned to fit the second ball member34. A second ball joint cage 32 includes a second ball joint cage stud36 that is operable to be inserted through a threaded aperture 52 on anouter surface of an external fixator ring 54 or other second externalsupport to secure the second ball joint 30 to an outer surface of anexternal fixator ring or other external support. The second ball joint30 is connected to a threaded elongated member 28. The second ball stud36 as well as the second ball member 34 may have one or more additionalslots 40 or nuts (not shown) operably connected thereto to tighten andlock the stud or ball in the desired positions. The slots 40 may use anytype head fastener known to the skilled artisan, e.g., slotted,Phillips, hex, socket, high-torque or other fastener/head.

It is to be appreciated that the configuration of the second ball stud36 may be varied to accommodate various designs of the apertures in theexternal fixator ring 54 and to improve the ease of connecting thesecond ball stud 36 to the external fixator ring 54.

FIG. 5B is a cutaway view of a portion of another embodiment of anexternal fixation strut of the present disclosure. In this embodiment,the second ball stud 36 has a smooth outer surface. The second ball stud36 is operable to be received in an aperture 53, which has an smoothinner surface, and substantially locked in place by a set screw 55inserted into aperture 57 of the external fixator ring 54. The aperture53 is aligned at an angle that substantially corresponds to the shape ofthe angled tip of the set screw 31, thereby increasing the contact areabetween the second ball studs 36 and the set screw 55.

Dynamic loading on the contact surface between the second ball stud 36and the set screw 55 can cause the contact surface to deform andultimately cause the second ball studs 36 to become loosened. Thus, thesecond ball studs 36 can be configured to have grooves defined thereinto allow for optimal gripping and to accommodate for the dynamic loadingof the contact surface.

FIG. 5C is a cutaway view of a portion of another embodiment of anexternal fixation strut of the present disclosure. In this embodiment,the second ball stud 36 has a smooth outer surface and includes acircumferential groove 37. FIG. 5D is a cutaway view of a portion of yetanother embodiment of an external fixation strut of the presentdisclosure. In this embodiment, the second ball stud 36 has a smoothouter surface and includes a circumferential groove 37 and a conical tip39. The second ball stud 36 is operable to be received in an aperture53, which has an smooth inner surface, and substantially locked in placeby a set screw 55 inserted into aperture 57 of the external fixator ring54. The conical tip 39 allows for better guidance for the insertion ofthe second ball stud 36 and increased contact surface between the secondball stud 36 and the inner surface of the aperture 53 for improvedstability. In addition, the inclusion of a conical tip 39 increases theeffective length of the second ball stud 36 and further improves thestability of the second ball stud 36 in the aperture 53. It is to beappreciated that, although not shown in FIGS. 5A-D, the first ball joint35 and the first ball member 14 can be similarly configured as discussedin FIGS. 5A-D.

FIGS. 6A and 6B are a perspective view and a cross sectional view of aball joint lockable by a split ball joint cage, respectively. The balljoint 30 includes a split ball joint cage 32 configured to receive aball 34. The split ball joint cage 32 is divided into upper and lowerportions 32 a and 32 b that substantially encapsulate the ball 34. Theupper portion 32 a includes bores 54 a and 54 b defined therethrough,and the low portion 32 b includes corresponding threaded apertures (notshown) defined therein operable to receive fasteners 56 a and 56 b thatare inserted through bores 54 a and 54 b. The fasteners 56 a and 56 bsecure the ball 34 within the split ball joint cage 32 a and 32 b andlimit the motion of the ball 34. The ball 34 passes through a ball jointaperture 50 that is sized and proportioned to fit the ball 34. A ballstud 36 is operable to secure the ball 34 to an external fixator ring orother external supports (not shown). The split ball joint cage 32 a isconnected to a threaded elongated member 28 and allows angular androtational alignment of the external fixation strut (not shown) relativeto the ball 34.

Shown in FIG. 6C is another embodiment of a ball joint lockable by apartially split ball joint cage. The ball joint 30 includes a partiallysplit ball joint cage 32 adapted to fit a ball 34. The partially splitball joint cage 32 includes a gap 120 defined therethrough, and the gap120 partially splits the ball joint cage 32 into first and second splitportions 122 and 124. The first split portion includes a bore 54 adefined therethrough, and the second portion includes a threadedaperture (not shown) that is operable to receive a fastener 56 a that isinserted through the bore 54 a. The ball 34 passes through a ball jointaperture 50 that is sized and proportioned to fit the ball 34, and thefastener 54 a secures the ball 34 within the partially split ball jointcage 32 and limit the motion of the ball 34.

FIG. 7 is a perspective view of a ball joint lockable by a threaded balljoint cage cap. The threaded ball joint 30 includes a ball cage having afirst threaded portion 32 a and a threaded locking member 32 b operableto engage the surface of a threaded ball member 34. The threaded balljoint cages 32 a and 32 b are operable to be coupled to hold the ball 34therein. The first threaded portion 32 a is operable to mate with athreaded portion of the threaded locking member 32 b to limit the motionof the threaded ball 34. The ball 34 passes through a threaded balljoint aperture 50 that is sized and proportioned to fit the threadedball 34. A threaded ball stud 36 is operable to secure the threaded ball34 to an external fixator ring or other external supports (not shown).The threaded ball joint cage 32 is connected to a threaded elongatedmember 28 and allows angular and rotational alignment of the externalfixation strut (not shown) relative to the ball 34.

FIG. 8 is a perspective view of a ball joint lockable by split ball. InFIG. 8, the split ball joint 30 includes a ball joint cage 32 adapted tofit a split ball 34. The split ball 34 includes an aperture 58 definedtherethrough, and the aperture 58 allows a split ball stud 36 to beinserted through the split ball 34. The split ball stud 36 has athreaded end portion and a smooth intermediate portion such that whenthe split ball stud 36 is inserted through the aperture 58, theintermediate portion expands the aperture 58. The expansive forceexerted on the walls of the aperture 58 frictionally secures the ball 34and cage 32 in the desired positions. The threaded end of the threadedball stud 36 is operable to secure the split ball 34 to an externalfixator ring or other external supports (not shown). The split balljoint cage 32 is connected to a threaded elongated member 28 and allowsangular and rotational alignment of the external fixation strut (notshown) relative to the ball 34.

FIG. 9 is a perspective view of a ball joint lockable by a set screw. InFIG. 9, the ball joint cage 32 includes a threaded radial bore 114defined therethrough and a set screw 116 inserted through the threadedradial bore 114. The tip of the set screw 116 exerts a frictional forceon the second ball member 34 to fix the second ball member 34 in oneorientation. In some embodiments, the ball joint cage 32 may beconfigured to receive additional set screws 116 to increase the totalfrictional force on the second ball member 34.

FIG. 10 is a side view of one embodiment of the external fixation strutof the present disclosure attached to an external fixation device. Anexternal fixation strut 10 is connected between a first external fixatorring 80 and a second external fixator ring 82. FIG. 10 depicts a singleexternal fixation strut 10 disposed between the first external fixatorring 80 and the second external fixator ring 82 for simplicity sake. Theskilled artisan will readily understand that numerous (e.g., 4, 6, or 8)external fixation struts 10 may be attached at various positions aboutthe external fixator rings, that the angle of the external fixationstrut 10 relative to the first external fixator ring 80 and the secondexternal fixator ring 82 may be varied, and that the length of theexternal fixation strut 10 may be varied and adjusted.

A first ball joint cage 12 is secured to the external fixator ring 80 orother external supports. The external fixation strut 10 includes a firstball joint cage 12 that houses a first ball member 14. The first ballmember 14 includes a first ball stud 16 that passes through an aperture(not shown) in the first external fixator ring 80 to secure the firstball member 14 to the external fixator ring 80 or other externalsupports. The first ball joint cage 12 allows angular and rotationalalignment of the external fixation strut relative to first ball member14. This movement allows the first ball joint cage 12 to be secured atdifferent angles relative to the first external fixator ring 80 or otherfirst external support.

A telescoping strut housing 18 extends from the first ball joint cage 12and has an aperture (not shown) extending longitudinally from the firstball joint cage 12. The telescoping strut housing 18 includes atelescoping housing adjustment aperture 20 defined therethrough. Anadjustment sleeve 22 is positioned in the axial bore (not shown) of thetelescoping strut housing 18. The adjustment sleeve 22 is slidablewithin the bore (not shown) to allow adjustment of the coarse end-to-endlength “A” of the external fixation strut 10 in a rapid manner. Themovement of the adjustment sleeve 22 in the axial bore (not shown) ofthe telescoping strut housing 18 allows the distance to be changed andin turn change the end-to-end length of the external fixation strut 10.

The adjustment sleeve 22 includes a sleeve fastener 24 positionedthrough the telescoping housing adjustment aperture 20 to secure theadjustment sleeve 22 to the telescoping strut housing 18. Thetelescoping housing adjustment aperture 20 also serves as a window toallow positioning and referencing of the adjustment sleeve 22 and or thethreaded elongated member 28 to aid in the adjustment of the end-to-endlength of the external fixation strut 10. The graduation marks 74indicate the lengths of the external fixation strut 10 as a relativevalue, rather than the distance from some predetermined specific length.The graduation marks do not necessarily have to be based on atraditional measuring system, or indicate the effective length of thestrut at all. For instance, the graduation marks could indicate thepercentage of total rod extension, or daily increments for cases wherethe translation takes place over an extended period of time. Referenceto a neutral position can be useful to set the base members at apredetermined “neutral” position.

An adjustment mechanism 26 is rotatably coupled to an end portion of theadjustment sleeve 22 and threadably connected to a threaded elongatedmember 28. The adjustment mechanism 26 may be rotated to engage thethreads of the threaded elongated member 28 and thereby adjustlongitudinally the end-to-end length “A” of the external fixation strut10 in a gradual manner. The threaded elongated member 28 includes asecond ball joint 30 with a second ball joint cage 32 adapted to fit asecond ball member 34. The second ball member 34 includes a second ballstud 36 that passes through an aperture (not shown) in the secondexternal fixator ring 82 to secure the second ball joint 30 to anexternal fixator ring 82 or other second external support.

The second ball joint cage 32 allows angular and rotational alignment ofthe external fixation strut 10 relative to second ball member 34. Thismovement allows the second ball joint cage 32 to be secured at differentangles relative to the second external fixator ring 82 or other secondexternal support.

FIG. 11 is a perspective view of one embodiment of the external fixationdevice having 6 connecting rods to immobilize bone segments. Theexternal fixation device includes a first external fixator ring 80 and asecond external fixator ring 82 that surround a bone (not shown). Thefirst external fixator ring 80 and a second external fixator ring 82 areconnected by 6 external fixation struts 10 a-10 f. Each of the externalfixation struts (10 a, 10 b, 10 c, 10 d, 10 e, and 10 f) includes afirst articulatable ball joint (not shown) that houses a first ball (notshown). The first ball (not shown) includes a first ball stud (notshown) that passes through a slot (not shown) into a threaded aperturein the external fixator ring 80.

Since there are multiple external fixator struts, it is desirable to beable to uniquely identify each strut so that the strut lengthadjustments for each strut can be tracked and implemented. Aninformation indicator may be mounted onto or embedded into the strutsfor identifying the struts. In some embodiments, the informationindicator may be a physical identifier, such as inscription, paper, orlabel of a code, color, or serial number corresponding to relevantinformation. Examples of the relevant information embodied orrepresented by the information indicator may include the type of thestrut, the maximum or minimum strut length, strut number, etc. In someembodiments, the information indicator may be an electronic identifier.One common method of identification includes a radiofrequency (RF)sensor that wirelessly communicates with a radio frequency transmitter(RFID) located on the adjustment mechanism of the external fixatorstrut. Another strut number identifier may include a bar code readerthat counts a specific number of grooves on the adjustment mechanism ofthe external fixator strut or communicates with magnetic strip locatedon the adjustment mechanism of the external fixator strut. In anotherembodiment, strut number identifier includes a sensor that receivesinformation from a touch memory button located on the adjustmentmechanism of the external fixator strut. Another embodiment of thepresent invention provides that the strut number is determined manuallyand allow the tool to engage the adjustment mechanism and rotates theadjustment mechanism on the desired number of turns. In otherembodiments, the information indicator may be any other device suitableto embody or represent information or a combination of the types ofindicators discussed in the present application.

A telescoping strut housing (not shown) extends from the firstarticulatable joint (not shown) to an adjustment sleeve (not shown) andthreaded elongated member (not shown) to a second ball. The second ball(not shown) includes a second ball stud (not shown) that passes into athreaded aperture of the external fixator ring or other fixation device82.

The methods of the present disclosure may be performed with a subject,e.g., a human or another vertebrate animal. One or more bones (of thesubject) to be fixed may be selected. Any suitable bone(s) may beselected, such as a long bone(s) and/or at least a pair of bonesconnected via an anatomical joint. Exemplary bones include leg bones(femur, tibia, and fibula), arm bones (humerus, radius, and ulna), footbones (calcaneus, talus, metatarsals, and phalanges), wrist/hand bones(carpals, metacarpals, and phalanges), etc. In exemplary embodiments,one or more bones including at least one long bone may be selected.

An external fixation device may be constructed along and at leastpartially around the selected bone(s). The external fixation device mayinclude a plurality of rings fixed in position relative to one anotherby numerous external fixation struts secured to the rings.

The external fixation device may be connected to the selected bone(s).Connection may be performed at any suitable time, such as before,during, and/or after construction of the external fixation device. Forexample, the external fixation device may be assembled and thenconnected to bone, or individual external fixation device members orexternal fixation device sub-assemblies may be connected to the bonebefore the external fixation device is fully assembled. Connection ofthe external fixation device to bone may include placing connectors,such as wires, pins, screw, and/or rods, among others, through the skinand into, through, and/or around the selected bone.

The external fixation device may be reconfigured while it is connectedto the one or more selected bones. Reconfiguration may include adjustingthe length, angle, position, and/or connection site of one or moreexternal fixation device components, particularly external fixationstruts. In some embodiments, reconfiguration may involve lengtheningand/or shortening one or more (or all) external fixation struts of theexternal fixation device. In some embodiments, reconfiguration mayinvolve replacing one or more external fixation struts with a differentconnecting rod(s). The different connecting rod may be of differentsize, pivotability, adjustability, shape, and/or the like.

The external fixation device may be braced to facilitatereconfiguration. Bracing the external fixation device may stiffen and/orstabilize the external fixation device such that reconfigurationproduces fewer undesired changes to the external fixation devicestructure as the external fixation device is weakened and altered duringreconfiguration. Bracing may be performed by securing at least one braceto the external support. In some examples, the brace may be configuredto be clipped onto the external fixation device members before the braceis fully secured to the external fixation device members. For example,the brace may include one or more external fixation device engagementelements that are biased to opposingly engage one or more respectiveexternal fixation device members. In any case, each engagement elementmay be secured in place on the external fixation device member byoperating a user control, manually or with a tool. Furthermore, therelative spacing and angular disposition of the engagement elements maybe fixed by operating a user control, either the same user control(s)for securing the engagement element to a frame member or a distinct usercontrol.

In some examples, the brace may include one or more movable joints, andthe brace may be installed in engagement with the external fixationdevice members with one or more of the joints in a movableconfiguration. The movable joints then may be adjusted to a locked(fixed) configuration. Alternatively, or in addition, the brace mayinclude a plurality of movable joints and one or more of the movablejoints may be locked before or during brace placement onto the frame,and one or more other of the movable joints may be locked after braceplacement onto the external fixation device.

The brace may be removed after frame reconfiguration. Accordingly, thebrace may be installed with the frame (and connecting rod) fixing boneand removed with the frame reconfigured and still fixing bone. The bracethus may be present on the external fixation device for only a fractionof the time that the external fixation device is fixing bone.

It is contemplated that any embodiment discussed in this specificationcan be implemented with respect to any method, kit, reagent, orcomposition of the disclosure, and vice versa. Furthermore, compositionsof the disclosure can be used to achieve methods of the disclosure.

It will be understood that particular embodiments described herein areshown by way of illustration and not as limitations of the disclosure.The principal features of this disclosure can be employed in variousembodiments without departing from the scope of the disclosure. Thoseskilled in the art will recognize, or be able to ascertain using no morethan routine experimentation, numerous equivalents to the specificprocedures described herein. Such equivalents are considered to bewithin the scope of this disclosure and are covered by the claims.

All publications and patent applications mentioned in the specificationare indicative of the level of skill of those skilled in the art towhich this disclosure pertains. All publications and patent applicationsare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more,” “at least one,”and “one or more than one.” The use of the term “or” in the claims isused to mean “and/or” unless explicitly indicated to refer toalternatives only or the alternatives are mutually exclusive, althoughthe disclosure supports a definition that refers to only alternativesand “and/or.” Throughout this application, the term “about” is used toindicate that a value includes the inherent variation of error for thedevice, the method being employed to determine the value, or thevariation that exists among the study subjects.

As used in this specification and claim(s), the words “comprising” (andany form of comprising, such as “comprise” and “comprises”), “having”(and any form of having, such as “have” and “has”), “including” (and anyform of including, such as “includes” and “include”) or “containing”(and any form of containing, such as “contains” and “contain”) areinclusive or open-ended and do not exclude additional, unrecitedelements or method steps.

The term “or combinations thereof” as used herein refers to allpermutations and combinations of the listed items preceding the term.For example, “A, B, C, or combinations thereof” is intended to includeat least one of: A, B, C, AB, AC, BC, or ABC, and if order is importantin a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.Continuing with this example, expressly included are combinations thatcontain repeats of one or more item or term, such as BB, AAA, MB, BBC,AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan willunderstand that typically there is no limit on the number of items orterms in any combination, unless otherwise apparent from the context.

All of the compositions and/or methods disclosed and claimed herein canbe made and executed without undue experimentation in light of thepresent disclosure. While the compositions and methods of thisdisclosure have been described in terms of preferred embodiments, itwill be apparent to those of skill in the art that variations may beapplied to the compositions and/or methods and in the steps or in thesequence of steps of the method described herein without departing fromthe concept, spirit and scope of the disclosure. All such similarsubstitutes and modifications apparent to those skilled in the art aredeemed to be within the spirit, scope and concept of the disclosure asdefined by the appended claims.

What is claimed is:
 1. An external fixation strut having a longitudinalaxis defined therein, the fixation strut comprising: a strut housinghaving an axial bore defined therethrough; a first ball joint coupled toan end portion of the strut housing, the first ball joint including afirst ball joint cage and a first ball member, the first ball memberbeing rotatably coupled to the first ball joint cage, the first balljoint cage including a bore defined therethrough, and the first ballmember including a circumferential groove defined therein; a pininserted through the bore of the first ball joint cage and at leastpartially into the circumferential groove of the first ball member to atleast partially limit rotation of the first ball member relative to thefirst ball joint cage; an adjustment sleeve slidably disposed within theaxial bore, the adjustment sleeve and the strut housing being releasablycoupled by a connector; an elongated member; a second ball joint coupledto an end portion of the elongated member; and an adjustment mechanismhaving a bore defined therethrough, the elongated member being disposedthrough the bore, the adjustment mechanism being operable to adjust alongitudinal position of the elongated member relative to the adjustmentsleeve.
 2. The external fixation strut of claim 1, wherein the struthousing includes an aperture defined in a wall of the strut housing, theaperture extends longitudinally along the strut housing, the adjustmentsleeve includes a radial bore, and the connector includes a screwdisposed through the aperture of the strut housing and received in theradial bore.
 3. The external fixation strut of claim 2, wherein theconnector includes a washer having a central opening defined therein,the washer is disposed on an outer surface of the strut housing, and thescrew is disposed through the central opening of the washer, through theaperture of the strut housing, and received in the radial bore.
 4. Theexternal fixation strut of claim 1, wherein the first ball jointincludes a first ball stud extending outwardly from the first ballmember, and the first ball stud is operable to be received in anaperture in a first external support member.
 5. The external fixationstrut of claim 4, wherein the second ball joint includes a second balljoint cage; a second ball member rotatably coupled to the second balljoint cage; and a second ball stud extending outwardly from the secondball member, the second ball stud being operable to be received in anaperture in a second external support member.
 6. The external fixationstrut of claim 4, wherein the first ball stud includes an end portion.7. The external fixation strut of claim 4, wherein the first ball studincludes a smooth outer surface, a circumferential groove defined in theouter surface, and a conical tip.
 8. The external fixation strut ofclaim 4, wherein an orientation of the first ball member relative to thefirst ball joint cage is operable to be substantially fixed.
 9. Theexternal fixation strut of claim 8, wherein the first ball joint cageincludes a radial gap defined therethrough, the radial gap partiallysplits the first ball joint cage into first and second split portions,the first split portion includes a first aperture defined therethrough,the second split portion includes a second aperture definedtherethrough, and the first and second apertures are operable to receivea fastener.
 10. The external fixation strut of claim 8, wherein thefirst ball member includes an aperture defined therethrough, theaperture is operable to receive a split ball stud disposed through theaperture, the split ball stud includes an end portion and a flared endportion operable to expand the aperture when the split ball stud isinserted through the aperture.
 11. The external fixation strut of claim8, wherein the first ball joint cage includes a first portion and alocking member operable to engage a surface of the first ball membersuch that when the locking member is engaged with the first portion themovement of the first ball member is substantially limited.
 12. Theexternal fixation strut of claim 8, wherein the first ball joint cageincludes a radial bore, a locking screw is disposed through the radialbore of the first ball joint cage, an end portion of the locking screwexerts a frictional force on the first ball member such that movement ofthe first ball member is substantially limited.
 13. The externalfixation strut of claim 1, wherein the adjustment sleeve includes alongitudinally extending slot defined therethrough.
 14. The externalfixation strut of claim 1, wherein the adjustment mechanism includes alocking mechanism.
 15. The external fixation strut of claim 1, furthercomprising an information indicator coupled to the adjustment sleeve orthe strut housing.
 16. The external fixation strut of claim 15, whereinthe information indicator includes an electronic information identifier.17. The external fixation strut of claim 1, further comprising a devicefor electronically identifying a strut.
 18. The external fixation strutof claim 1, further comprising an electronic device for monitoring strutadjustments.
 19. An external fixation strut comprising: a strut housinghaving an axial bore defined therethrough and an aperture defined in awall of the strut housing, the aperture extending longitudinally alongthe strut housing; an adjustment sleeve slidably disposed within theaxial bore, the adjustment sleeve and the strut housing being releasablycoupled by a connector, the adjustment sleeve including a radial bore,and the connector including a screw disposed through the aperture of thestrut housing and received in the radial bore; an elongated member; afirst ball joint coupled to an end portion of the strut housing, thefirst ball joint including a first ball joint cage including a boredefined therethrough; a first ball member rotatably coupled to the firstball joint cage and including a circumferential groove defined therein;a pin inserted through the bore of the first ball joint cage and atleast partially into the circumferential groove of the first ball memberto at least partially limit rotation of the first ball member relativeto the first ball joint cage; and a first ball stud extending outwardlyfrom the first ball member, the first ball stud being operable to bereceived in a ring aperture in an outer or inner surface of a firstexternal fixator ring; a second ball joint coupled to an end portion ofthe elongated member; and an adjustment mechanism that adjusts alongitudinal position of the elongated member relative to the adjustmentsleeve.
 20. A method of interconnecting first and second fixator ringswith a strut, adjusting the strut to a pretreatment strut length, andmaking strut length adjustments during treatment, the rings eachincluding a plurality of apertures defined in an inner or outer surfaceof the ring, the method comprising: providing a first part of the strut,the first part including a first ball joint coupled to an end portion ofa strut housing, the strut housing having an axial bore definedtherethrough, the first ball joint including a first ball stud, a firstball joint cage and a first ball member, the first ball member beingrotatably coupled to the first ball joint cage, the first ball jointcage including a bore disposed therethrough, and the first ball memberincluding a circumferential groove defined therein; inserting a pinthrough the bore of the first ball joint cage and at least partiallyinto the circumferential groove of the first ball member to at leastpartially limit rotation of the first ball member relative to the firstball joint cage; providing a second part of the strut, the second partincluding a second ball joint coupled to an end portion of an elongatedmember; the elongated member being coupled to an adjustment mechanism,the adjustment mechanism being coupled to an adjustment sleeve, and thesecond ball joint including a second ball stud; disposing the adjustmentsleeve within the axial bore of the strut housing; connecting the firstball stud of the first ball joint to a first aperture of the firstfixator ring; connecting the second ball stud of the second ball jointto a second aperture of the second fixator ring; positioning theadjustment sleeve relative to the strut housing to arrive at thepretreatment strut length; releasably coupling the adjustment sleeve tothe strut housing; and translating, using the adjustment mechanism, theelongated member to adjust the strut length.
 21. The method of claim 20,wherein the first ball stud extends outwardly from the first ballmember.
 22. The method of claim 20, wherein the first ball joint cageincludes a radial gap splitting the first ball joint cage into first andsecond split portions, the first split portion includes a first aperturedefined therethrough, the second split portion includes a secondaperture defined therein, the first and second apertures are operable toreceive a fastener, the first ball stud extends outwardly from the firstball member, and the method further comprises inserting a fastenerthrough the first aperture in the first split portion and into thesecond aperture thereby locking the first ball member in a spatialorientation by engaging an end portion of the fastener in the secondaperture.